Patent GB-654779-A (GB)
Title: Manufacture of brightening agents
Filed: 1948-06-24
Abstract: Compounds of general formula <FORM:0654779/IV (b)/1> wherein X is alkyl or alkoxy and Y1 and Y2 are primary amino groups or secondary or tertiary amino groups substituted by lower aliphatic (optionally substituted, e.g. preferably by hydroxyl), alicyclic or araliphatic radicles or by radicles of the benzene series which may have further non-auxochromic substituents such as sulphuric acid, sulphuric acid amide, halogens, methyl, methoxy, ethoxy, acylamino or carboxyl groups, are prepared by condensing 1 mol. of 4-nitro-41-aminostilbene-2 : 21-disulphonic acid with 1 mol. of a cyanuric halide and with 1 mol. of a reactive functional derivative of a lower fatty acid or a lower alkyl ester of chloroformic acid and with 2 mols. of the same or different amino bases (ammonium, primary or secondary amines), and reducing the nitro group to the amino group, the above stages being effected in any suitable order.  The nitro group may be reduced and acylated after condensation of the sulphonic acid with the halide and replacement of halogen by amino groups, or the sulphonic acid may be acylated, the nitro group reduced, condensation effected with the halide, optionally condensed with 1 mol. of an amine, and the product treated with the amino base, or the cyanuric halide may be reacted with an amine, e.g. sulphanilic or metanilic acid before condensation with the disulphonic acid, the remaining halogen atom replaced by an amino group and the nitro group reduced and acylated.  Reduction is effected by iron filings and acid.  Hydroxy groups may be substituted into the above aliphatic radicles by the use of mono-ethanolamine, di-ethanolamine or 2 : 3-dihydroxypropylamine or by condensing a primary amino group with lower aldehydes, e.g. preferably formaldehyde, to yield methylolamino groups.  In examples: (1) cyanuric chloride is condensed at 0-4 DEG C. with an aqueous solution of 4-amino-41-acetylaminostilbene-2 : 21-disulphonic acid, the two remaining halogen atoms are replaced by treatment with methylaniline in weak acid solution first at 20-22 DEG C. and then at 90-95 DEG  C., the product is separated by salting out, and dried, it may also be obtained by reacting the chloride with 4 : 41-nitroaminostilbene-2 : 21-disulphonic acid and then with methylaniline as above, the nitro group being reduced with iron and hydrochloric acid and the amino group so formed acetylated in aqueous solution with acetic anhydride, in place of methylaniline cyclohexylamine or benzylaniline may be used to give the correspondingly substituted melamine derivative; (2) the above condensation product is treated at 20-25 DEG  C. with metanilic acid and at 90-95 DEG  C. with 25 per cent ammonia, the product isolated, dried and optionally treated with formaldehyde by the method of Specification 595,065, alternatively aniline may be used in place of ammonia and in each instance either amine may be used in the initial amination at 20-25 DEG  C.; (3) the same condensation product is reacted with aniline and then with 25 per cent ammonia, in place of aniline methylaniline, benzylamine, phenylethylamine, cyclohexylamine or p-methylcyclohexylamine may be used; (4) the above condensation product is treated with 25 per cent ammonia at 20-22 DEG  C. and at 90-95 DEG  C., the product isolated and optionally treated with formaldehyde as in (2), in place of ammonia dimethylamine or diethanolamine may be used; (5) cyanuric chloride is condensed with 4-amino-41 - propionylaminostilbene - 2 : 21 - disulphonic acid and the halogens replaced by reaction with aniline and ammonia; (6) cyanuric chloride and 4 : 4 - nitroaminostilbene - 2 : 21 - disulphonic acid are condensed as in U.S.A. Specification 2,368,844, reacted at 20-25 DEG  C. with metanilic acid and 90-95 DEG  C. with aniline when the product is reduced with iron filings and hydrochloric acid, treated at room temperature with methyl chloroformate in aqueous solution in the presence of a mineral acid binding agent, e.g. sodium acetate, and the product isolated by salting out, and dried, it may also be made by condensing the chloride with 4-amino-41-carbomethoxyaminostilbene - 2 : 21 - disulphonic acid, metanilic acid and aniline and ethylmay replace methyl-chloroformate; and in (7) the condensation product of (1) is agitated under reflux for 7 hours at 95-100 DEG  C. with o-toluidine and crystalline sodium acetate, anhydrous sodium carbonate is added and excess toluidine removed by steam distillation, the remainder is filtered hot and the product isolated by salting out, it may also be obtained by condensing the chloride with 4-nitro-41-aminostilbene-2 : 21-disulphonic acid, treating with o-toluidine, reducing the nitro group and acetylating the amino group so obtained; o-chloraniline or o-anisidine may replace the o-toluidine.ALSO:Compounds of general formula <FORM:0654779/IV (c)/1> (for preparation see Group IV (b)), wherein X is alkyl or alkoxy and Y1 and Y2 are primary secondary or tertiary amino groups substituted by lower aliphatic (optionally substituted, e.g. preferably by hydroxyl), alicyclic or araliphatic radicles or by radicles of the benzene series which may have further non-auxochromic substituents such as sulphonic acid, sulphonic acid amide, halogens, methyl, methoxy, ethoxy, acylamino or carboxyl groups, are brightening and optical bleaching agents, particularly for protein fibres, e.g. wool, before and especially after bleaching. They are a light yellow colour.  They can be used for dyeing from a neutral or weakly acid bath and are fast towards acid, laundering, alkalis, light and sea water.  In an example (8) bleached wool yarn with a slightly yellowish appearance is dyed for 30 minutes at 40-50 DEG  C. in a bath with a liquor ratio 1 : 30 containing a compound of the above formula in which X is CH3-and Y1 and Y2 are C6H4NCH3, Glauber's salt and 80 per cent acetic acid, mixed with cold water and air-dried when the yarn has a much whiter appearance than the untreated material.